Corneal confocal microscopy may help to distinguish Multiple System Atrophy from Parkinson’s disease

Multiple system atrophy (MSA) and Parkinson’s disease (PD) have clinical overlapping symptoms, which makes differential diagnosis difficult. Our research aimed to distinguish MSA from PD using corneal confocal microscopy (CCM), a noninvasive and objective test. The study included 63 PD patients, 30 MSA patients, and 31 healthy controls (HC). When recruiting PD and MSA, questionnaires were conducted on motor and non-motor functions, such as autonomic and cognitive functions. Participants underwent CCM to quantify the corneal nerve fibers. Corneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) values in MSA are lower than PD (MSA vs. PD: CNFD, 20.68 ± 6.70 vs. 24.64 ± 6.43 no./mm2, p < 0.05; CNFL, 12.01 ± 3.25 vs. 14.17 ± 3.52 no./mm2, p < 0.05). In MSA + PD (combined), there is a negative correlation between CNFD and the Orthostatic Grading Scale (OGS) (r = −0.284, p = 0.007). Similarly, CNFD in the only MSA group was negatively correlated with the Unified Multiple System Atrophy Rating Scale I and II (r = −0.391, p = 0.044; r = −0.382, p = 0.049). CNFD and CNFL were inversely associated with MSA (CNFD: β = −0.071; OR, 0.932; 95% CI, 0.872 ~ 0.996; p = 0.038; CNFL: β = −0.135; OR, 0.874; 95% CI, 0.768–0.994; p = 0.040). Furthermore, we found the area under the receiver operating characteristic curve (ROC) of CNFL was the largest, 72.01%. The CCM could be an objective and sensitive biomarker to distinguish MSA from PD. It visually reflects a more severe degeneration in MSA compared to PD.


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Not relevant for this study. Participants were recruited at the Department of Neurology, Affiliated Hospital of Xuzhou Medical University Local ethic committee of the Affiliated Hospital of Xuzhou Medical University CCM is used only when the patient is initially enrolled Parkinson's disease patients and the Multiple system atrophy patients are diagnosed based on the established diagnostic criteria.Healthy individuals without any previous neurological disorders were chosen as controls, either from volunteers or spouses of patients.Study participants younger than 35 and older than 85 were excluded.There were no socially constructed or socially relevant categorization variables used in our manuscript Sex-and/or gender was based on self-reporting.The exact group size of female and male participants are provided in the manuscriptEcological, evolutionary & environmental sciences study designAll studies must disclose on these points even when the disclosure is negative.We require information from authors about some types of materials, experimental systems and methods used in many studies.Here, indicate whether each material, system or method listed is relevant to your study.If you are not sure if a list item applies to your research, read the appropriate section before selecting a response.